Windows only: The Instant Boss timer application sets up a number of work dashes with breaks. Especially useful for practicing Merlin Mann's 10+2*5 procrastination hack, you commit to working a certain amount of minutes, then you get a break, then the Instant Boss tells you to "Get back to work!" I'm revising the Lifehacker book in 60-minute dashes using my trusty kitchen timer, but I may switch over to Instant Boss (especially on the road). Instant Boss is a free download (donations encouraged) for Windows only. Thanks, Jayvant!